<p>This thesis describes a grey-box model for the dimensionalstability properties (i.e. curl and twist) of the carton boardproduced at AssiDomän Frövi paper mill in Sweden.AssiDomän Frövi AB is one of Sweden major cartonboard manufacturer, and produces some 350000 ton of board peryear.</p><p>Curl is defined as the departure from a at form, and it mayseriously affect the processing of the paper. For this reason,customers impose quite restrictive limits on the allowedcurvatures of the board. So, it is becoming more and moreimportant to be able to produce a carton board with a curlwithin certain limits. Due to the economic significance of thecurl problem, much research has been performed to find sheetdesign and processing strategies to eliminate or reducecurl.</p><p>The approach we used to tackle this problem is based ongrey-box modelling. The reasons for such an approach is thatthe physical process is very complex and nonlinear. The inuenceof some inputs is not entirely understood, and besides itdepends on a number of unknown parameters andunmodelled/unmesurable disturbances.</p><p>One of the main part of the model is based on classicallaminate theory which is used to model the dimensionalstability of multi-ply board. The main assumption is that eachlayer is considered as an homogeneous elastic medium.</p><p>The model is then complemented with a sub-model forunmodelled/umeasurable disturbances which are described asstates of a dynamical system, and estimated by means of anextended Kalman filter.</p><p>The simulated curvatures show a general agreement with themeasurements. However, the prediction errors are too large forthe model to be used in an effective way, and a bigger efforthas to be carried out in order to improve the physicalsub-models.</p><p>A chapter of this thesis discusses the modelling of thewet-end part of the paper machine with Dymola, a modelling toolfor simulation of large systems based on Modelica language.</p>

This thesis describes a grey-box model for the dimensionalstability properties (i.e. curl and twist) of the carton boardproduced at AssiDomän Frövi paper mill in Sweden.AssiDomän Frövi AB is one of Sweden major cartonboard manufacturer, and produces some 350000 ton of board peryear. Curl is defined as the departure from a at form, and it mayseriously affect the processing of the paper. For this reason,customers impose quite restrictive limits on the allowedcurvatures of the board. So, it is becoming more and moreimportant to be able to produce a carton board with a curlwithin certain limits. Due to the economic significance of thecurl problem, much research has been performed to find sheetdesign and processing strategies to eliminate or reducecurl. The approach we used to tackle this problem is based ongrey-box modelling. The reasons for such an approach is thatthe physical process is very complex and nonlinear. The inuenceof some inputs is not entirely understood, and besides itdepends on a number of unknown parameters andunmodelled/unmesurable disturbances. One of the main part of the model is based on classicallaminate theory which is used to model the dimensionalstability of multi-ply board. The main assumption is that eachlayer is considered as an homogeneous elastic medium. The model is then complemented with a sub-model forunmodelled/umeasurable disturbances which are described asstates of a dynamical system, and estimated by means of anextended Kalman filter. The simulated curvatures show a general agreement with themeasurements. However, the prediction errors are too large forthe model to be used in an effective way, and a bigger efforthas to be carried out in order to improve the physicalsub-models. A chapter of this thesis discusses the modelling of thewet-end part of the paper machine with Dymola, a modelling toolfor simulation of large systems based on Modelica language. / NR 20140805

Eucalyptus microcarpa Maiden (Grey Box) is a common and widespread woodland and open forest in south-eastern Australia. In Victoria, it features prominently in woodlands throughout the southern, central and northern plains environments, and also in the box-ironbark forests of the Great Dividing Range. Temperate grassy woodlands have been extensively modified since European settlement of Victoria and consequently the native biodiversity associated with them has undergone a dramatic decline. Paramount to this decline has been the landscape-scale reduction in tree cover associated with agricultural clearing, which in some regions approaches 95% or pre-European extent. Similar to most other woodland tree species, E. microcarpa is today restricted to small remnant patches or relict individuals within agricultural landscapes where extensive stands once occurred.

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Zur Produktion von gewirkten Textilien werden mehrere Nadeln auf eine Legebarre gesetzt, die durch Servoantriebe positioniert werden. Aufgrund der erzwungenen Bewegung kann der Antriebsstrang bei hohen Drehzahlen zur Schwingung angeregt werden. Die richtige Wahl der Steuerkurven ist daher eine sehr wichtige und anspruchsvolle Aufgabe, die durch ein Antriebsstrangmodell unterstützt werden soll. Dafür wird am Beispiel eines Teststands ein Modell des Antriebsstranges in MATLAB/Simulink® entwickelt. Für das Antriebsstrangmodell müssen eine geeignete Modellordnung und Modellparameter gewählt werden. Die unbekannten Modellparameter werden durch eine Parameteridentifikation ermittelt. Mit einer Validierung wird ein geeignetes Anregungsspektrum für die Bestimmung der Modellordnung und die Parameteridentifikation ermittelt.

With the advancements made in the field of data science, smart IoT devices are be-coming increasingly common. Consequently, this creates an increased number of targets for hackers to potentially exploit. This is a study about ethically hacking a robot vacuum, the Roborock S7, and evaluating the security of the target system. The DREAD and Stride threat models are used in order to find potential exploits. These exploits are then tested on the vacuum. Four tests were done on the system: scan-ning, denial-of-service attack, man-in-the-middle sniffing and man-in-the-middle tampering. The study found that the vacuum is relatively secure against web threats with weaknesses found surrounding its handling of its own network and lack of re-sistance to denial-of-service attacks on the DHCP protocol. / Med de framsteg som sker inom datavetenskap och teknologi blir IoT-enheter allt vanligare i hemmen. Detta medför en ökad mängd enheter med potentiella sårbar-heter som hackare kan utnyttja. Denna rapport handlar om att etiskt hacka en ro-botdammsugare av modell Roborock S7 och utvärdera dess säkerhet mot internet-hot. DREAD och STRIDE används som hotmodeller för att hitta sårbarheter. Sår-barheterna testas sedan på dammsugaren. Fyra tester utfördes på system: scanning, denial-of-service-attack, man-in-the-middle-avlyssning och man-in-the-middle-av-lyssning med manipulering. Rapporten hittade att dammsugaren är resonabelt säker mot internethot men med svagheter i hur enheten hanterar sitt egna nätverk samt ett bristande motstånd mot en denial-of-service-attack genom DHCP-protokollet.

<p>The purpose of this thesis work was to develop an automatic fault detection system for surveillance of bearing temperature in hydropower turbines. The parameters used except the bearing temperature were cooling water temperature and cooling water flow. A simple static model based on data sampled every minute was developed to estimate the bearing temperature. Then a detector for detection of change in bearing temperature based on the CUSUM-algorithm was designed. Since the amount of data was very small the developed model was too uncertain to be used in a working system.</p><p>The designed fault detection system showed to work well for the available data. It is, however, recommended that the performance of the system should be evaluated using more data. Another model based on data sampled once every minute for at least a year has to be developed before the system can be fully evaluated. The results shown were:</p><p>• The fault detection system can discover fast and slow changes in bearing temperature.</p><p>• No false alarms were given for measuring faults and sensor faults of the types used in this thesis. If a measuring fault occurs for too long there will be an alarm.</p><p>The fault detection algorithm was also implemented in Delphi to be used in a working system over the Internet where for example trends and alarms will be presented.</p> / <p>Syftet med examensarbetet var att utveckla ett automatiskt feldetekteringssystem för övervakning av bärlagertemperaturen i vattenkraftturbiner. De ingående parametrarna förutom bärlagertemperaturen var kylvattentemperaturen och kylvattenflödet. En enkel statisk modell baserad på data samplat en gång per minut togs fram för att estimera bärlagertemperaturen. Därefter utvecklades en detektor för att upptäcka avvikelser i bärlagertemperaturen baserad på CUSUM-algoritmen. På grund av en för liten mängd data var den framtagna modellen alltför osäker för att kunna implementeras i ett fungerande system.</p><p>Det framtagna feldetekteringssystemet visade sig fungera bra för de data som fanns tillgängliga. Det är däremot rekommenderat att utvärdera systemets prestanda med längre dataserier. En ytterligare modell baserad på minutdata över ett år måste tas fram innan systemet kan fungera på riktigt. De resultat som erhölls var:</p><p>• Feldetekteringssystemet klarar av att upptäcka abrupta och långsamma avvikelser av bärlagertemperaturen.</p><p>• Inga falsklarm ges då det är enstaka mätfel eller givarfel av sådan typ som tagits upp i arbetet. Pågår ett mätfel alltför länge ges dock ett larm.</p><p>Feldetekteringsalgoritmen implementerades även i Delphi för att kunna användas i ett fungerande system över Internet där t.ex. trendkurvor och larmsignaler skall kunna presenteras.</p>

<p>I Australien är vattenresurserna begränsade. För lantbrukare är tillgängligheten på vatten mycket viktig. På grund av det torra klimatet kan inte de Australiensiska bönderna förlita sig på nederbörden. Bevattningssystemen är därför en viktig del i jordbrukningsindustrin.</p><p>Bevattningsområdet i Coleambally ligger i södra New South Wales nära gränsen till staten Victoria. Bevattningsnätet i Coleambally förser ofta bevattningskanalerna med för mycket vatten för att vara säker på att lantbrukarna får den mängd vatten de behöver. På grund av denna tillförsel av överskottvatten går stor mängd av vatten förlorad. Design av ett bättre reglersystem skulle kunna minska den stora förlusten av vatten.</p><p>En matematisk modell beskrivande dynamiken av bevattningssystemet är ett bra redskap vid en design av ett bättre reglersystem. Syftet med det här projektet var att genom systemidentifiering bygga en matematisk modell av bevattningssystemet. Modellen syftade till att beskriva vattennivån i en sträcka av bevattningskanalerna, sträckan i kanalen skulle ha två olika typer av luckor, en typ där vattnet strömmar över luckan och en annan typ där vattnet strömmar under luckan. En modell byggdes genom att parametrar från en vald modellstruktur estimerades från experimentella data. Data samlades under ett experiment som utfördes på en bevattningskanal i Coleambally.</p><p>Resultatet från systemidentifieringen blev en första ordningens output error grey box modell. Modellen visar goda resultat vid validering och bör kunna användas vid design av ett bättre reglersystem. Modellen visar så god överensstämmelse med valideringsdata att den även kan användas för olika fall av simulering.</p> / <p>Water resources in Australia are limited. For a farmer the access to water is crucial and due to the dry climate the farmers in Australia can not rely on precipitation. Irrigation is therefore a very important part of the farming industry.</p><p>The Coleambally Irrigation Area is situated in the southern parts of New South Wales close to the border of Victoria. The Irrigation Network often supplies the irrigation channels with too much water to be sure that the demand of water is satisfied. Due to this over supply a great amount of water gets wasted. Design of a bettercontrol system would be able to reduce the water wastage.</p><p>A mathematical model describing the dynamics of the irrigation system can be used as a tool for the control system design. The aim of this project was to build a mathematical model with the system identification approach. The model should be able to describe the downstream water level of a single pool of an irrigation channel which has both undershot and overshot gates. A model was built by estimating unknown parameters of a chosen model structure from a set of experimental data. The data was collected from an experiment performed on the real irrigation system in Coleambally.</p><p>The result of the system identification was a first order output error grey box model. The model performs well on validation data and may therefore be used for design of a more efficient control system. The model gave such good results that it additionally may be used for various simulation purposes.</p>

Over the recent years, the software industry has faced a steady increase in the number of exposed and exploited software vulnerabilities. With more software and devices being connected to the internet every day, the need for proactive security measures has never been more important. One promising new technology for making software more secure is fuzz testing. This automated testing technique is based around generating a large number of test cases with the intention of revealing dangerous bugs and vulnerabilities. In this thesis work, a new direction within grey-box fuzz testing is evaluated against previous work. The presented approach uses sampled probability data in order to guide the fuzz testing towards program states that are expected to be easy to reach and beneficial for the discovery of software vulnerabilities. Evaluation of the design shows that the suggested approach provides no obvious advantage over existing solutions, but also indicates that the performance advantage could be dependent on the structure of the system under test. However, analysis of the design itself highlights several design decisions that could benefit from more extensive research. While the design proposed in this thesis work is insufficient for replacing current state of the art fuzz testing software, it provides a solid foundation for future research within the field. With the many insights gained from the design and implementation work, this thesis work aims to both inspire others and showcase the challenges of creating a probability-based approach to grey-box fuzz testing.

This research deals with the modeling and control of a plasticating twin screw extruder (TSE) that will be used to obtain consistent product quality. The TSE is a widely used process technology for compounding raw polymers. Compounding creates a polymer with improved properties that satisfy the demand of modern plastic applications. Modeling and control of a TSE is challenging because of its high nonlinearity, inherent time delay, and multiple interactive dynamic behavior. A complete methodology is proposed in this thesis to design an advanced control scheme for a TSE. This methodology was used to develop a model predictive control scheme for a laboratory scale plasticating TSE and to implement the control scheme in real-time. The TSE has a processing length of 925 mm and a length to screw diameter ratio (L/D) of 37. High density polyethylenes with different melt indices were used as processing materials. Manipulated variables and disturbance variables were selected based on knowledge of the process. Controlled variables were selected using a selection method that includes a steady state correlation between process output variables and product quality variables, and dynamic considerations. Two process output variables, melt temperature (Tm) at the die and melt pressure (Pm) at the die, were selected as controlled variables. A new modeling approach was proposed to develop grey box models based on excitation in the extruder screw speed (N), one of the manipulated variables. The extruder was excited using a predesigned random binary sequence (RBS) type excitation in N and nonlinear models relating Tm and Pm to N were developed using this approach. System identification techniques were used to obtain model parameters. The obtained models have an autoregressive moving average with exogenous (ARMAX) input structure and the models explain the physics of the extrusion process successfully. The TSE was also excited using a predesigned RBS in the feed rate (F) as a manipulated variable. Models relating Tm and Pm to F were developed using a classical system identification technique; both models have ARMAX structures. The model between Pm and F was found to give excellent prediction for data obtained from a stair type excitation, indicating that the obtained models provide a good representation of the dynamics of the twin screw extruder. Analysis of the TSE open loop process indicated two manipulated variables, N and F, and two controlled variables, Tm and Pm. Thus, a model predictive controller (MPC) was designed using the developed models for this 2X2 system and implemented in real-time. The performance of the MPC was studied by checking its set-point tracking ability. The robustness of the MPC was also examined by imposing external disturbances. Finally, a multimodel operating regime was used to model Tm and N. The operating regime was divided based on the screw speed, N. Local models were developed using system identification techniques. The global model was developed by combining local models using fuzzy logic methodology. Simulated results showed excellent response of Tm for a wide operating range. A similar approach was used to design a global nonlinear proportional-integral controller (n-PI) and a nonlinear MPC (n-MPC). Both the controllers showed good set-points tracking ability over the operating range. The multiple model-based MPC showed smooth transitions from one operating regime to another operating regime. / Process Control